docs: update related packages sections

[stdlib-bot]

This PR

• updates the related packages section of READMEs to include links to related packages.

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
array/base/filled2d-by	$\color{green}104/104$ $\color{green}+100.00\%$	$\color{green}5/5$ $\color{green}+100.00\%$	$\color{green}1/1$ $\color{green}+100.00\%$	$\color{green}104/104$ $\color{green}+100.00\%$
array/base/fliplr4d	$\color{green}303/303$ $\color{green}+100.00\%$	$\color{green}13/13$ $\color{green}+100.00\%$	$\color{green}3/3$ $\color{green}+100.00\%$	$\color{green}303/303$ $\color{green}+100.00\%$
array/base/flipud4d	$\color{green}295/295$ $\color{green}+100.00\%$	$\color{green}12/12$ $\color{green}+100.00\%$	$\color{green}3/3$ $\color{green}+100.00\%$	$\color{green}295/295$ $\color{green}+100.00\%$
blas/ext/base/sapx	$\color{green}432/432$ $\color{green}+100.00\%$	$\color{green}42/42$ $\color{green}+100.00\%$	$\color{green}4/4$ $\color{green}+100.00\%$	$\color{green}432/432$ $\color{green}+100.00\%$
math/base/special/cfloor	$\color{green}252/252$ $\color{green}+100.00\%$	$\color{green}5/5$ $\color{green}+100.00\%$	$\color{green}2/2$ $\color{green}+100.00\%$	$\color{green}252/252$ $\color{green}+100.00\%$
string/last	$\color{green}177/177$ $\color{green}+100.00\%$	$\color{green}20/20$ $\color{green}+100.00\%$	$\color{green}1/1$ $\color{green}+100.00\%$	$\color{green}177/177$ $\color{green}+100.00\%$

The above coverage report was generated for the changes in this PR.